Conventional normal weirs are inherited with significant afflux and submergence of area upstream of the weir. Various weirs of modified plan form like oblique weirs, diagonal weirs, Duckbill weirs, Labyrinth weirs etc. have been suggested in the past to enhance their discharging capacity and to restrict the afflux. Present study has been carried out on W-planform weirs to investigate their discharge characteristics under free flow conditions in a rectangular channel. The efficiency of the weirs is found better than the normal weir. A discharge equation has been proposed using the data collected in this study. The proposed equation computes the discharge within

±5% error. Sensitivity of the weir, ie, change of discharge due to unit change in head is also carried out which indicates that the weir is more sensitive at the low head and low vertex angle.